It has become more common to store a variety of information including personal information in user terminal apparatuses such as mobile phones, personal digital assistants (PDAs), and portable multimedia players (PMPs). Accordingly, there is an increasing need to prevent unauthorized use of a user terminal apparatus. To this end, a user terminal apparatus can be locked and released by the use of passwords or fingerprints. However, in such a locking method, a user needs to get authorized by inputting his/her fingerprint or passwords every time using the user terminal apparatus in a locked status, and if the user has lost the user terminal apparatus, unauthorized use can be prevented only if the user locked up the user terminal apparatus before.